In 1945 in het artikel “The research center for group dynamics at Massachusetts Institute of Technology” schrijft Lewin(p.130): “the conditions of group life and the forces which bring about change or which resist change should be investigated. The term ‘dynamics’ refers to these forces . Volgens Weisbord (1987, p.80) heeft Lewin aan dit idee gewerkt als onderdeel van zijn field theorie – wat later ook bekend is geworden als de krachtenveldtheorie: “He believed that some difference in these forces – “a weakening of the barriers or a strengthening of the driving forces” – was required to produce the unfreezing that began a change. For the resulting change to become permanent after moving to a new level, refreezing is required to freeze at the higher level. He held that it was more effective to weaken the barriers than to strengthen the drivers.

In 1947 werd postuum Lewin’s artikel “Frontiers in group dynamics” gepubliceerd. Daarin staat op p. 13 te lezen: “Change and constancy are relative concepts; group life is never without change, merely differences in the amount and type of change exist. Even verderop in de paragraaf getiteld: “Constancy and Resistance to Change”, schrijft hij dat “Only by relating the actual degree of constancy to the strength of forces toward or away from the present state of affairs can one speak of degrees of resistance or ‘stability’ of group life in a given respect. En op de pagina daarna (p.14) schrijft hij dat “the practical task of social management, as well as the scientific task of understanding the dynamics of group life, requires insight into the desire for and resistance to, specific change (p. 14).